If humans create fires in vegetation dominated areas it can have a devastating affect. It can occur in grasslands, moorlands, forests and heaths. The climate plays a big part on how bad the fire can be. If it is windy then the fires will move much move quickly and will burn faster. Also the type of vegetation plays a part in the extent of the fire. Fires are strongest in forests that are dense and are very dry. This again disrupts the succession in the same way as deforestation does by wiping out lots of vegetation leaving the soil exposed. This can also lead to soil erosion, as there is no cover for the soil from vegetation. This will also then lead to secondary succession.
Overgrazing and ploughing also have a negative affect on plant succession. Overgrazing is where there are too many animals grazing on an area of land, more than that area of land is able to support. When these animals are on the land they are destroying the vegetation. Animals will eat the grass that is on the land and this is therefore stopping the plant succession. The grass is unable to develop over time as animals are eating it. The grass will not be able to develop into new species and the plant succession will be stopped. Ploughing has a similar affect on the land as over grazing does. When farmers farm land, they will put chemicals into the soil and this can do a lot of damage. Some chemicals can kill flowers and grass, therefore disrupting the plant succession.
There are a number of positive roles that humans can play in plant succession.
Some areas of land, such as national parks are protected by humans. In these areas of land there is a lot of vegetation that is free to grow and cannot be built upon and cannot be farmed on. There are a number of national parks in Britain e.g. South Downs and the New Forest. Plants will be free to grow here and plant succession will not be disrupted here. So in areas of land that are protected plant succession should be able to take place without any disruptions. But there could be some disruptions that humans cannot control e.g. changes in climate.
Afforestation, this is where humans will replant trees. The land that they will replant the trees on may have previously been deforested. When an area of vegetation gets deforested humans should then replant the trees so that they are not doing as much damage to the environment. If humans replant trees or shrubs in an area then they are going to be encouraging plant succession and therefore this being a positive role that humans are playing in plant succession.
Humans play positive and negative roles in plant succession. I believe that they have more of a negative affect on plant succession than they do a positive affect. There are a number of ways in which they disrupt plant succession, and consequently stopping plant succession in some areas. They do have some positive affects on plant succession but I do not believe that these do not balance out the damage that humans do to plant succession.
